Hi,<br />dont sure but using sp_attach_single_file_db you can do it, it will make a clean and new log file for you while attaching your db.<br />BOL says what should be taken care while using this option :<br /><br /> <blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Remarks<br />When sp_attach_single_file_db attaches the database to the server, it builds a new log file and performs additional cleanup work to remove replication from the newly attached database.<br /><br />Use sp_attach_single_file_db only on databases that were previously detached from the server using an explicit sp_detach_db operation.<br /><br />Use sp_attach_single_file_db only on databases that have a single log file. Do not use this stored procedure on databases that have multiple log files.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote"><br /><br /><br />[<img src='/community/emoticons/emotion-1.gif' alt='' />]<br />Regards<br /><br /><br />Hemantgiri S. Goswami<br />ghemant@gmail.com<br />"Humans don't have Caliber to PASS TIME , Time it self Pass or Fail Humans" - by Hemantgiri Goswami<br />

Another way might be to use dbcc rebuild_log as described here:http://www.windowsitpro.com/SQLServer/Article/ArticleID/8636/8636.html
Make sure you read closely through the explanations at the end of the chapter "Shrinking an Active Log File in SQL Server 7.0".
However, the question is still valid. How have you lost the t-log file? Or is this a hypothetical scenario question? Anyway, that's a good example where a sound backup and disaster recovery plan is essential.

Well, in this case am I guessing right that you didn't properly take the database offline?
Chances are more than good that this action corrupted your database, so that you are ot able to recover. You have a recent backup, haven't you?

I haven't tried this myself yet. However, what I have once tried was to copy and burn an online database on CD, Well, I got it on CD, but I wasn't able to bring it back online again. I even looked at the files with a hex editor, but didn't succeed. But it's worth a try. Especially when you don't have a recent backup.

I create a new database whose name is the same as my old database. And then I shutdown my SQL Server. I delete the data file of this new database (but don't delete log file) and copy the data file of my old database to replace. It doesn't work...